Consistent Discipline is the bridge between setting a goal and achieving it.
Without consistent discipline hardly any goal can be achieved. In the other words, having consistent discipline is a key and fundamental factor in achieving any goal in life.
The length of the discipline must be until the goal is achieved that's why I said Consistent Discipline. By this I mean, short term disciplines will not lead to achievement and that's just simply waste of time.
Example 1: Passing an exam
Imagine Jack has to pass a difficult exam next week. If he studies without proper discipline and only for 2-3 days then he will not pass his exam. The rule says he must study consistently with proper discipline until the exam has been passed. If he gives up during the process he has just wasted his time.